Terminal enclosure for transformer



' July 22, 1969 F. R. DENTREMONT 3,457,360

TERMINAL ENCLOSURE FOR TRANSFORMER Filed Jun s. 1967 3 457,360 TERMINAL ENCLOSURE FOR TRANSFORMER Franklin R. DEntremont, Dover, N.H., assignor to General Electric Company, a corporation of New York Filed June 8, 1967, Ser. No. 644,522 Int. Cl. H01h 17/56, 17/00 US. Cl. 174138 2 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF INVENTION This invention relates to terminal enclosures and, more particularly, to terminal enclosures to enclose the various terminals of an instrument transformer.

In the instrument transformer field, it has long been the practice to provide terminal enclosures for the terminals of instrument transformers. These enclosures are provided to secure the connections to the terminals and prevent tampering with such connections. The enclosure is also considered desirable to shield the various terminals from exposure to the elements and also to prevent persons or metallic objects from coming in contact with such terminals. As will be understood, the various terminals of an instrument transformer could, under some circumstances, provide a lethal shock to a person contacting them. Of course, should a metallic object contact the terminals, the transformer would be shorted with possible damage to the transformer or to instruments connected thereto.

Many types of terminal covers have been used previously. One example of a secondary terminal enclosure is disclosed in Patent No. 3,283,062. Many of the terminal enclosures which are presently available are designed for use with a single terminal and also do not enable the closing of the terminal when the transformer is not in use. It is considered desirable, in the instrument transformer field to provide a terminal enclosure which may be used jointly with a pair of terminals which are adjacent to each other on the transformer. -It is also considered desirable that the terminal enclosure be transparent so that the condition of the connection to the terminals may be determined without removing the enclosure.

It is therefore one object of this invention to provide a novel terminal enclosure for instrument transformers.

A further object of this invention is to provide a one- United States Patent SUMMARY or INVENTION In carrying out this invention in one form, a terminal enclosure is provided in the form of a one-piece enclosure made of clear plastic, electrically insulating material. The enclosure is substantially of open box construction having two adjacent side members and substantially square shaped end members. One side member is provided with openings to allow leads to be connected to the terminals. The other side member has a locking extension designed to snap over a portion of the transformer. Holes are provided in the locking extension to allow a sealing wire to be used for sealing the enclosure to the transformer.

The invention which is sought to be protected will be particularly pointed out and distinctly claimed in the claims appended hereto. However, it is believed that the invention and the manner in which its various objects and advantages are obtained, as well as other objects and advantages thereof, will be more clearly understood from the following detailed description of a preferred embodiment thereof, particularly when considered in the light of the accompanying drawing.

BRIEF DESCRIPTION OF DRAWING FIGURE 1 is a perspective view of a preferred form of terminal enclosure according to the preferred embodiment of this invention;

FIGURE 2 is a top view of the terminal enclosure shown in FIGURE 1;

FIGURE 3 is a front view of the terminal enclosure shown in FIGURE 1;

FIGURE 4 is a side or end view of the terminal enclosure shown in FIGURE 1;

FIGURE 5 is a sectional view taken on the lines 5-5 of FIGURE 2;

FIGURE 6 is a partial sectional view showing the terminal enclosure mounted on a transformer; and

FIGURE 7 is a front view of one form of instrument transformer showing the terminal enclosure of this invention secured thereto.

DESCRIPTION OF PREFERRED EMBODIMENT Reference will now be made to the drawing in which like numerals are used to indicate like parts throughout the various views. The drawing shows the present preferred embodiment of a one-piece, clear plastic terminal enclosure 10. While the following description sets forth the specific details of the preferred embodiment of this invention, it will be clear to those skilled in this art, that various changes may be made in the constructional details without departing from the scope of the defined invention.

FIGURE 1 shows a perspective view of the preferred embodiment of the terminal enclosure 10. As is clear from FIGURE 1, the enclosure 10 comprises an open box-like structure having adjacent side walls 12 and 14, with end walls 16 and 18, only end wall 16 being clearly shown in FIGURE 1. The end walls 16 and 18 are substantially square shaped as is more particularly shown in FIGURE 4. One side wall, such as front Wall 12, is provided with a pair of openings 20, 22 which allow lead wires to be brought in to the terminals of the transformer. The shape of openings 20, 22 is more clearly shown in FIG- URE 3. In the preferred form, the openings 20, 22 are substantially semi-circularly shaped at the top with short straight side walls, so as to conform to the shape of the lead wire entering to the terminal. The relation between openings 20, 22 and the terminals of the transformer are more clearly shown in FIGURE 7. The other side wall, such as the top wall 14, is provided with a locking extension 24 which comprises two identical tab members 26 and 28. Each of tabs 26 and 28 is provided with a hole 3 30, 32 respectively for a sealing wire connection as will be more clearly described with respect to FIGURE 6. The shape of the tabs is more clearly seen in FIGURES 4 and 5 of the drawing.

Where the side Walls 12 and 14 meet in the adjacent edge, a notch 34 is cut out or formed and a tab member 36 extends into such notch. The construction of the notch 34 and the tab 36 are more clearly seen in FIGURES 2, 3 and 5 of the drawing. The purpose of notch 34 and tab 36 will be more clearly seen from a consideration of FIGURES 6 and 7.

FIGURE 6 is a partial sectional view of enclosure in place on a transformer 40 While FIGURE 7 shows a front view of one form of a transformer 40 with enclosure 10 mounted thereon. As can be most clearly seen in FIGURE 6, the transformer 40 is provided with a locking and sealing member 42 which has a front projecting portion 44 which fits into the notch 34 and over the tab 36. The locking and sealing member 42 has a rear tab portion 46 which fits between the tabs 26 and 28 on the side wall 14. The rear tab 46 also has a hole 48 which mates with the holes 30 and 32 on tabs 26 and 28, respectively, to receive a sealing wire to securely seal the enclosure 10 to the transformer 40.

Transformer 40 has a pair of terminals 50 and 52, one on each side of the locking and sealing member 42. This is most clearly seen from FIGURE 7. As can be seen from FIGURE 7, the terminals 50, 52 are in line with the openings 20, 22, in the front wall 12 of enclosure 10. This enables lead wires (not shown) to extend from the terminals 50, 52 through the openings 20, 22 when the enclosure 10 is in place on the transformer 40, in the manner clearly shown in FIGURE 7. As will be understood, after the lead wires (not shown) are secured to the terminals 50, 52, the enclosure 10 will be slid over the lead wires (not shown) and tilted slightly so that the front projection 44 will fit over tab 36. The enclosure 10 will then be snapped over the terminals 50, 52 with the tabs 26, 28 snapping on each side of rear tab 46 of the member 42. A sealing wire may then be inserted into the holes 30, 48 and 32 to seal and lock the enclosure securely to the transformer 40.

Of course, it will be understood, that the enclosure 10 is preferably made of a clear plastic, electrically insulating material. In the preferred embodiment, the preferred material is a clear, thermoplastic polycarbonate resin. AS

will be apparent, other types of resins could be used. However, it is preferred that the enclosure be transparent so that the condition of the terminal connections may be observed without removing the enclosure 10.

From the above it will be apparent that by means of this invention there is provided a one-piece terminal cover which may be readily used to enclose the terminals of a transformer. While the preferred form of an invention is shown in conjunction with a particular type of transformer in FIGURES 6 and 7, it will of course, be evident that such terminal enclosure may be used in conjunction with other types of transformers and terminals. Obviously, many changes may be made in the various constructional details of the preferred embodiment of this invention without departing from the spirit and scope thereof, particularly as it is defined in the appended claims.

What is claimed as new and which it is desired to be secured by Letters Patent of the United States is:

1. A terminal enclosure for the terminals of a transformer comprising an open, box type enclosure having a pair of adjacent side walls and a pair of end walls, one of said side walls having a pair of openings for terminal leads, the other of said side walls having a locking extension which extends away from said one of said side walls, a notch formed in the adjacent portions of said side walls and a tab on said one of said side walls extending into said notch.

2. A terminal enclosure for the terminals of a transformer as claimed in claim 1 in which said locking extension comprises a pair of identical tab members, each of said ta-b members having a sealing hole therein.

References Cited UNITED STATES PATENTS 855,550 6/ 1907 Atkinson 220-394 3,112,148 11/1963 Wochner 174-92 X 3,283,062 11/ 1966 DEntremont 174-138 LEWIS H. MYERS, Primary Examiner D. A. TONE, Assistant Examiner US. Cl. X.L. 

